The first step was to remove the trim piece around the iDrive controller. Just grab it and pull up hard, there are no screws, just clips. Be careful of the wire connecting the iDrive controller.
After pulling the panel off stick your finger under the shifter and push the surrounding trim out.
Then you need to remove the drive mode selector and traction control buttons, there are two clips, one on the front and one on the back that need to be depressed in order to get the buttons out. They are circled in the picture below.